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In Oblique projection parallel projectors are imagined to emanate from every point of an imaginary object and which strike the projection plane at any angle different from ninety degrees - as opposed to orthographic projectors which always strike a plane of projection at ninety degrees. In Orthographic projection and Oblique Projection, parallel lines in space appear parallel on the projected image. Because of its simplicity Oblique Projection is used exclusively for Pictorial purposes. This article is about technical drawings. ...
Oblique Pictorial
In an Oblique Pictorial drawing, the displayed angles among the axes as well as the foreshortening factors (scale) are arbitrary. The distortion created thereby is normally attenuated by aligning one plane of the imaged object parallel with the plane of projection thereby creating a true shape, full-size image of the chosen plane. A special case is to draw the receding axis scale at half-size and at an angle of 45-degrees. This called Cabinet Projection and is popular in furniture illustrations.
Unavoidably, all cylindrical projections have an east-west stretching away from the equator by a factor equal to the secant of the latitude, compared with the scale at the equator.
Azimuthal projections have the property that directions from a central point are preserved (and hence, great circles through the central point are represented by straight lines on the map).
Some azimuthal projections are true perspective projections; that is, they can be constructed mechanically, projecting the surface of the Earth by extending lines from a points of perspective (along an infinite line through the tangent point and the tangent point's antipode) onto the plane.
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